Project Summary/Abstract This project will use a multilevel longitudinal cohort study design to assess whether changes in Community Tobacco Environmental (CTE) factors, measured as community compliance with tobacco control policies and community density of tobacco vendors and advertisement, are associated with adolescent tobacco use initiation in urban India. The project will also assess how family level factors moderate and individual level factors mediate the associations between CTE factors and adolescent tobacco use. Annually, an estimated 1 million deaths in India are attributable to tobacco use making it a leading cause of premature mortality. India became an early adopter of the WHO Framework Convention for Tobacco Control. A key set of India's tobacco control policies pertain to Articles 8, 13 and 16 of the FCTC regarding secondhand smoke exposure, access to tobacco products and tobacco promotion. India's policies include smoke-free laws; restrictions on tobacco advertisements; bans on the sale of tobacco products to minors and within 100 yards of educational institutions, recent bans on the sale of gutkha (a particularly dangerous smokeless tobacco product), and new requirements for highly prominent warning labels on tobacco packaging. In addition, the recent emergence of e-cigarettes in the Indian tobacco marketplace will require new policy responses. Research data about community level compliance with tobacco control policies, access to and promotion of emerging products like e-cigarettes, and their association with youth tobacco use, are largely unavailable, and are needed to inform policy development. Therefore, we aim to: (1) Administer a comprehensive longitudinal population-based tobacco use risk factors survey on a cohort of 2,040 12-13 year old adolescents (and their parent) for four waves form baseline (Wave 1) to 36 months follow-up (Wave 4). (2) Concurrently, measure Community Tobacco Environmental factors in the 68 communities from where the adolescent sample will be drawn. We will use Geographic Information Systems data collection to map and audit tobacco vendors, COTPA defined public places, tobacco advertisements, availability of e-cigarettes, and compliance with tobacco control and smoke-free laws. (3) Estimate the longitudinal associations between CTE factors and adolescent tobacco use, and assess whether the associations are moderated by family level factors (e.g., parent tobacco use, household tobacco use policy, parenting factors, and household socioeconomic status), and meditated by individual level factors (e.g., perceived ease of access to tobacco including access to gutkha and e-cigarettes, perceived tobacco use norms, perceived tobacco use harms, exposure to tobacco ads, and exposure to secondhand smoke).The geographic scope will include Mumbai and Kolkata, India, cities that span from the West to the East coast of India, and represent large variations in adolescent tobacco use, socioeconomic development, cultural factors and Community Tobacco Environmental factors.